DataGrid edition 'EditItem' is not allowed for this view` when bound to a WPF DataGrid

Question

I've been reading about this at least for 4 hours, and seems to be the list type, but I have a situation:

A ObservableCollection that has a collection property.

I define the first DataGrid, and in the section

<DataGrid.RowDetailsTemplate>
    <DataTemplate>
        <!-- second Datagrid here, binding to Level2 property of my Observable collection -->
    </DataTemplate>
<DataGrid.RowDetailsTemplate>

Everything goes fine, all things on screen as I expected... but:

1. If try to modify DataGrid1 cells it allow me.
2. If try to modify DataGrid2 cells it throw me this exception 'EditItem' is not allowed for this view

What am I missing ?

This is my model:

public partial class Level1
{
    public Level1()
    {
        this.Level2 = new HashSet<Level2>();
    }

    public decimal IdLevel1 { get; set; }
    public decimal IdLevel2 { get; set; }
    public string StrDescripcionTipoAsociado {get;set;}

    public virtual Level2 Level2{ get; set; }
}

public partial class Level2
{
    public decimal IdLevel1 { get; set; }
    public decimal IdLevel3 { get; set; }

    public virtual Level3 Level3{ get; set; }
}

public partial class Level3
{
    public decimal IdLevel3 { get; set; }
    public decimal NumIdConcepto {get;set;}
    public string StrDescripcionConcepto {get;set;}
}

EDIT: XAML Code:

    <DataGrid Grid.Row="1" 
              ItemsSource="{Binding Level1}" 
              AutoGenerateColumns="False" 
              SelectionMode="Single"
              GridLinesVisibility="Vertical"
              CanUserAddRows="True"
              CanUserDeleteRows="True"
              x:Name="GridTipoAsociado">
        <DataGrid.Columns>
            <DataGridTemplateColumn Header="Tipo de asociado" x:Name="TipoUsuarioSeleccionado">
                <DataGridTemplateColumn.CellTemplate>
                    <DataTemplate>
                        <Label Style="{StaticResource ResourceKey=FontElemNivel1}" Content="{Binding StrDescripcionTipoAsociado}"/>
                    </DataTemplate>
                </DataGridTemplateColumn.CellTemplate>
                <DataGridTemplateColumn.CellEditingTemplate>
                    <DataTemplate>
                        <TextBox Style="{StaticResource ResourceKey=FontElemNivel2}" Text="{Binding StrDescripcionTipoAsociado }"/>
                    </DataTemplate>
                </DataGridTemplateColumn.CellEditingTemplate>
            </DataGridTemplateColumn>
        </DataGrid.Columns>
        <DataGrid.RowDetailsTemplate>
            <DataTemplate>
                <DataGrid Grid.Row="1" 
                          ItemsSource="{Binding Level2}" 
                          AutoGenerateColumns="False" 
                          SelectionMode="Single"
                          SelectionUnit="Cell"
                          GridLinesVisibility="Vertical"
                          CanUserAddRows="True"
                          CanUserDeleteRows="True"                            
                          x:Name="GridItems">
                    <DataGrid.Columns>
                        <DataGridTemplateColumn Header="Id Item">
                            <DataGridTemplateColumn.CellTemplate>
                                <DataTemplate>
                                    <Label Content="{Binding NumIdConcepto}"/>
                                </DataTemplate>
                            </DataGridTemplateColumn.CellTemplate>
                        </DataGridTemplateColumn>
                        <DataGridTemplateColumn Header="Items">
                            <DataGridTemplateColumn.CellTemplate>
                                <DataTemplate>
                                    <Label Content="{Binding Level3.StrDescripcionConcepto}"/>
                                </DataTemplate>
                            </DataGridTemplateColumn.CellTemplate>
                            <DataGridTemplateColumn.CellEditingTemplate>
                                <DataTemplate>
                                    <TextBox Text="{Binding Level3.StrDescripcionConcepto}"/>
                                </DataTemplate>
                            </DataGridTemplateColumn.CellEditingTemplate>
                        </DataGridTemplateColumn>
                    </DataGrid.Columns>
                </DataGrid>
            </DataTemplate>
        </DataGrid.RowDetailsTemplate>
    </DataGrid>

Answer 1

I tried this and the problem is that you have initialized your Level2 collection as Hashset<>. IEditableCollectionView.EditItem() throws this error while trying to update item in Hashset<>. I initialized the collection as List<> and it was working fine.

I am not sure why it is not able to update item in hashset, need to look deeper into it. But changing the Hashset<> to List<> will fix this error.

Hope it helps

Thanks

Answer 2

You might try this. Attach a BeginningEdit handler to your DataGrid and point to this code:

    private void Grid_BeginningEdit(object sender, DataGridBeginningEditEventArgs e)
    {
        //// Have to do this in the unusual case where the border of the cell gets selected.
        //// and causes a crash 'EditItem is not allowed'
        e.Cancel = true;
    }

This will only hit if you somehow manage to physically tap down on the border of the cell. The event's OriginalSource is a Border, and I think what may happen here is, instead of a TextBox or other editable element being the source as expected, this un-editable Border comes through for editing, which causes an exception that is buried in the 'EditItem is not allowed' exception. Canceling this RoutedEvent before it can bubble on through with its invalid OriginalSource stops that error occurring in its tracks.

Answer 3

Tks to @nit who give me the right path. Of course the problem reside on the base Type of EF collections

Hashet< T > And Datagrid need at least a List< T >, changing all my classes "those generated by Entity framework", give to me another problem, must make changes manually, and I have a lot of them.

My solution was to create a converter, that made the dirty work for me:

public class listToObservableCollection : BaseConverter, IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        HashSet<Level2> observableList = (HashSet<Level2>)value;
        return new ObservableCollection<Level2>(observableList);
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return (HashSet<Level2>)value;
    }
}

public abstract class BaseConverter : MarkupExtension
{
    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return this;
    }
}

And put it on the binding of my Datagrid2:

<!--part of my window definition--!>
xmlns:l="clr-namespace:Recursos;assembly=Recursos"
...
<!--part of my resources section--!>
<l:listToObservableCollection x:Key="listoToObservable"/>
...
<!--part of my datagrid definition--!>
ItemsSource="{Binding Level2,Converter={StaticResource listoToObservable}}"

The only thing on the air is how to make a generic converter, but for now it works fine.

Answer 4

I also solved this problem by using IsReadOnly="True".